Improvement in head-blocks



- 'DARIUS PARKHURST, or ST. LOUIS, MISSOURI.

IMPROVEMENT IN HEAD-BLOCKS.

Specification forming part of Letters Patent No. 123,507, dated February6, 1872.

To all whom it may concern:

Be it known that I, DARIUS PARKHURST, of St. Louis, in the county of St.Louis and State of Missouri, have made a certain new and useful ImprovedAdjustable Knee for Head- Blocks for Saw-Mills and I do hereby declarethat the following is a full and true description thereof, referencebeing had to the accompanying drawing and to the letters of referencemarked thereon.

The ordinary knees or sliding rests for headblocks, against which thelogs are held, are constructed with an upright standard or vertical partat right angles with its sliding or horizontal part. In the use of saidordinary sliding knees it is well known that in rolling a heavy log onthe head-block there is great danger of fracturing or breaking theuprights of said knees; and, also, that in turning the log in theposition required the head-block and knees are frequently broken by theforce and weight of the falling log. Further, it is known that theordinary knees are unadapted to accommodate the crooked and inconvenientshapes of logs, necessitating propping or blocking up, and also agreater propelling power; and thus much time and labor is involved inmanipulating and securing the logs properly to accomplish the differentpurposes of sawing.

The object, therefore, of this invention is to construct an adjustableor falling knee, which shall avoid the inconveniences aforesaid, and inthe use of which a more perfect manipulation of the logs is achieved.The nature, thereof relates chiefly to the arrangement of the upright orvertical part of the knee in a pivoted or hinged manner to itshorizontal part, so as to be readily adjusted to any required angle bymeans of a hand-lever and togglejoints; and also to the manner ofsupporting the said adjusted knee in position, all of which will nowmore fully be described.

To enable those skilled in the art to make and use my said improvement,I will now more fully describe the same, referring to the drawing, whichrepresents a side elevation; also, showing in dotted lines theadjustability of the falling knee.

The head-block rests and is operated in a proper carriage in the usualmanner. The

head-blocks support thereon the sliding rests or knees proper,consisting of the horizontal part A and vertical knee part A; Thehorizontal part A is arranged with tooth-racks to be actuated forwardand backward as usual.

hinged at b, said toggle-joints consisting of.

the arms B B, the opposite end of said joints being pivoted at b to avertical standard, 0, which forms part of the knee proper, as shown inthe drawing. The toggle-joints are operated by a hand-lever, D, which ispivoted to the standard 0 at b and further, said lever has an extensionarm, D, which is attached to the center joint b by the same bolt thatsecures the toggle-joint. The falling knee A, when adjusted by means ofthe hand-lever aforesaid, is supported by or abuts against an inclinedstandard or support, E, which is cast or forms also a part of thehorizontal knee part A, as clearly illustrated in the drawing. The saidstandards 0 and E are provided with eyebolts, to which the dogs areattached for holding the log in position against the knee A, as usual.

By such a manner of construction the falling knees A can be adjusted, asillustrated by dotted lines in the figure. Thus any serious concussionis prevented also, the log is propelled to the saw with less power, thepower being applied at the bottom, almost directly in line with thefalling knee.

\Vhen the log is dogged up against the knee it rests in position forsawing as usual. In turning the log the upper part of the falling kneesacts as a fulcrum and allows the log to slide easily down the face ofthe adjusted knee.

Further, by my said improvements the largersizes of logs can be placedon a commonsizedhead-block, the falling knees being adjusted asillustrated. Finally, the knees can be adjusted to suit all irregularshapes of logs, and especially it will be noticed that any taper can besawed by moving the knees in or out, as desired.

Having thus fully described my said im- 7 In testimony of said inventionI have hereprovements, what I claim is-- unto set my hand.

The falling knee A toggle-j oints B B, hand- DARIUS PARKHURST. lever D,its extension part D when said parts are hinged, in combination with thehorizon- In presence of-- tal knee part A having extension supports 0WILLIAM W. HERTHEL, E, substantially as and for the purpose set ROBERTBURNS.

forth.

